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An external PS for Naim CD3

A

aeon

pfm Member
Hi, I know that cd 3.5 has na option to be powered form *cap.

Can a cd3 be somehow moded to make use of external PSU?

Maybe some diy-cap be used for it?

Cheers

RaD
 
As the old adage goes: If there's one thing more lethal than incoming enemy fire - it's incoming friendly fire.....

The CD3 requires around 24 - 0 - 24 Volts DC to hit the main board which the internal regulators take down to the various circuits.
 
Can Cd3 be modded to make use of snaps?

They are cheap now on ebays and can be moded to use better regs etc...

Or maybe it's better to build some diy-cap?

RaD
 
Theoretically it could - or at least some of it could be pressed into service for split rail operation although there is no merit in paying a premium for a Snaps case and transformer. Better to start from scratch with a custom transformer and case.
 
The short answer is yes, of course it can be modified, but it will be no simple task.

I recently acquired a CD3 & fairly well impressed with it I am - it doesn't seem to have too much of the 'bad' side of the Naim sound about it, to my ears at least. Still, I bought it knowing how it could be improved & fully intend to modify it.

I think my first approach would be to have separate digital/analog supplies & then improve the regulation on the analog side.
I actually first opened the thing up over the weekend & was quite surprised to find about 11 regulators in there!Obviously care has been taken to separate all the supplies, but as we know well, these can be easily improved upon.
 
Wouldnt you have to drill holes and fit new connectors to get outside power rails into cd3? what about warranty?

mmmmmm I think it would only be worthwhile after a few years use !

taffyboy
 
Warranty?

Are you kiddin', right? :D

They aren't in production since late 90' of XX century! :)

For some time I'll stick with original, but sooner or later I would like to mod it, unless I'll be able to buy CDX :D


RaD
 
Aeon, I'm pretty sure it would be a doddle to mod a cd3 to accept an external power supply though you may have to cut a couple of tracks on the pcb or remount the internal regulators to accept an input supply from your psu.
drop me a mail at ctaylor at cmpinformation dot com and I'll forward a pdf of how its done in the cd3.5 and you can probably figure out how to do if from that.
cheers
Ced
 
Thank you. Is it similar to that can be found on acustica?

As far as I know, 3.5 differs a little from 3.

And I don't have it yet! I've been outbided :(

I have to gather more funds that I thought....

Till then

Radek
 
aahh not such good luck then.
But no, its really a schematic of the power supply and grounding layout. I'm pretty sure the analogue section is essentially the same between the 3 and 3.5 which is what you need, though the digial and dac stuff is different.
cheers
c
 
HI aeon,

I haven't had CD3 apart - yet ;) - but the differences are details: the CD3 uses the TDA1541 dac and CMD9 transport (for which the CDM9/44 can be substituted), the CD3.5 uses the Philips TDA1305 dac and VAM1205 transport (I think that's basically a CDM12.4 with a Hall-effect disc motor).

The different dac means the boards will be laid out a little differently - there may be photos here. Beyond that I expect Naim will have basically re-used the same basic circuit ideas, so the power supply arrangements are likely to be close. Nothing you couldn't trace out with pen, paper and a multimeter, anyway.
 
martin,
does this mean you have your mitts on a cd3 and are going to try non-os ing it?
could be very nice.
Ced
 
Hi Ced

Sorry to jump in but I'd like a copy of that .pdf too please. I'll send you a mail if that's OK.

It may help when I come to figure out where to tap power from inside a 3.5 in order to power a replacement clock. I'll be using one of Andy's regulators.

Physical placement ideas/experiences for the clock and SR would be of assistance too.

Lots of space beside that trafo ... ;)
 
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